Late-Infantile Neuronal Ceroid Lipofuscinosis (LINCL), also called Jansky-Bielschowsky syndrome or Neuronal Ceroid Lipofuscinosis Type II, is one of a group of rare disorders called the neuronal ceroid lipofuscinoses (NCLs). The various forms of NCL are generally classified by age of onset, though variations on these disorders exist. A later onset version called the juvenile form was originally referred to as Batten Disease, but now this term has come to encompass all forms of NCL. Batten Disease also belongs to a larger group of disorders referred to as lysosomal storage disorders.

Like all of the NCLs, LINCL is considered an inherited, progressive, neurodegenerative disease characterized by storage of lipopigments in the brain and other tissues. It is an autosomal recessive disorder. The gene responsible for most cases, CLN2, has been mapped to chromosome 11 (11p15 to be specific). Early development in these children is normal or mildly delayed, with the age of onset most typically being between ages 2 to 4 years. Multiple seizure types typically develop, and irregular muscle jerks, called myoclonic jerks, are typically prominent. Cognitive decline, motor problems, and vision failure with optic atrophy also characterize this disorder.

For the non-biologists reading this, lysosomes are organelles in a cell that contain digestive enzymes. Lysosomes primarily serve a waste-management function within the cell, digesting all kinds of “trash,” but they may also repair damage to other parts in a cell (e.g., the plasma membrane). Malfunctions of these lysosomes caused by mutations of the genes result in various kinds of problems caused by this impaired metabolic process, causing a progressive accumulation of this waste material. Therefore, malfunctions such as these are typically called lysosomal storage disorders. Specifically, mutations in the CLN2 gene result in the deficiency of an enzyme called tripeptidyl peptidase I (TPP-I), which is what is characteristic of LINCL. This is a lysosomal enzyme responsible for degrading membrane proteins, and measuring the amount of this enzyme with a special blood test is one step in the diagnostic process of LINCL. Although all tissues within the body are impacted by not having this enzyme to do its job, central nervous system (CNS) and retinal (pigmented epithelial) cells are the most sensitive, resulting in their progressive destruction.

Mary Payton’s consulting physicians seem to think that she has the classical version of LINCL, often referred to in the literature as cLINCL.